Thosha Thosha, one of the opponents in the Hidden Temple can be quite difficult. That's the Claw Party, up to five enemies all resistant to all types of magic except what they are named for. There's a recommended party from your walkthrough and the main guide.
But I found a more effective and reliable way. None of the claws resist generic damage from physical attacks. So the combination I found that works well is: Simon, Vhala, Ginasta, Carina. Start with the Ground Claw. Simon smacks it with Precise Strike, Vhala every turn alternates between Defensive Rain and Offensive Rain. By doing this, you render them completely unable to hurt the party. Meanwhille Ginasta starts shreding the Ground Claw with Pure Thrusts. During this time, Carina alternates between Shield of Purity and Mass Heal. By using this technique, you take them all part sequentially. Save the Shining Claw for last when Carina can join in
It may take a while (about 15 min.), but it grinds them to pieces with absolutely nothing they can do about it. All four characters have more than enough power to do it. You should have about 1/3rd of your Mana left at the end with no need to use potions of any kind. I like this method because the Magic Users like Robin and Altina are too fragile to take the kind punishment the Claws dish out. And Spellshock can wipe them out at a very inconvenient time.
But Vhala's repeated Defensive and Offensive Rains neuter them.
With these four characters, you turn this fight into the massacre of the Claws.